p = the number of the students who answered the item correctly q = the number of the students who answered the item incorrectly
s
2
= standard deviation of the test Arikunto, 2002:163
After the writer obtained the reliability score, the following step was to consult to the score with the r product moment table.
3.6.4 Difficulty Level
After the try out was conducted, each of the items were classified into difficulty level by using this formula:
JS B
P =
In which, P
= item difficulty B
= number of students who answered the item correctly JS
= number of students Arikunto, 1995: 212
The level of difficulty of each item was determined by using these following categorizations:
0 P ≤ 0, 3
is difficult 0, 3 P
≤ 0, 70 is medium
0,7 P ≤ 1
is easy Arikunto, 1995: 214
3.6.5 Discriminating Power
The discriminating power measures how well the test items arranged to identify the differences in the students’ competence.
The formula is:
JB BB
JA BA
D −
=
In which, D =discriminating
power BA
=number of students in the upper group who answered the item correctly
BB =number of students in the lower group who answered the item
correctly JA
=number of all students in the upper group JB
=number of all students in the lower group Arikunto,
1995: 218
The criteria of the discrimination index are: D = Negative is very poor
0.00 D ≤ 0, 20 is poor
0, 20 D ≤ 0, 40 is satisfactory
0, 40 D ≤ 0, 70 is good
0, 70 D ≤ 1.00 is excellent
Arikunto, 1995:225
CHAPTER IV RESEARCH FINDINGS AND ANALYSIS
In chapter IV, the writer discussed the try- out findings, the significant difference of pre- test and post- test, test of significance, the grades of achievement
and discussion of the research findings.
4.1 Try- out Findings
This discussion covered validity, reliability and item analysis.
4.1.1 Validity of Instrument
As mentioned in chapter III, validity refers to the precise measurements of the test. In this study, item validity was used to know the index validity of the test. To
know the validity of instrument, the writer used the Pearson Product Moment formula to analyze each item.
It was obtained that from 40 test items; there were 31 test items which were valid and 9 test items which were invalid. They were on number 5, 9, 15, 20, 21, 27,
33, 38, and 40 They were to be said invalid with the reason the computation result of their r
xy
value the correlation of score each item was lower than the r
table
value. The following was the example of item validity computation for item number 1,
and for the other items would use the same formula.
Table 4.1. The Table of Students’ score in Validity Computation No. Code X
Y X
2
Y
2
XY
1 T-15 1
37 1
1369 37
2 T-21 1
37 1
1369 37
3 T-12 1
35 1
1225 35
4 T-19 1
35 1
1225 35
5 T-4 1
35 1
1225 35
6 T-26 1
35 1
1225 35
7 T-25 1
34 1
1156 34
8 T-23 1
31 1
961 31
9 T-22 1
28 1
784 28
10 T-2 1
28 1
784 28
11 T-16 0
28 784
12 T-7 1
28 1
784 28
13 T-17 1
26 1
676 26
14 T-18 0
26 676
15 T-9 0
26 676
16 T-3 0
25 625
17 T-20 1
25 1
625 25
18 T-10 1
23 1
529 23
19 T-11 0
22 484
20 T-28 1
20 1
400 20
21 T-6 0
20 400
22 T-8 0
19 361
23 T-14 1
16 1
256 16
24 T-13 1
16 1
256 16
25 T-5 0
15 225
26 T-24 0
12 144
27 T-1 1
13 1
169 13
28 T-27 0
12 144
Σ 18 707
18 19537
502
r
xy =
{ }
{ }
∑ ∑
∑ ∑
∑ ∑
∑
− −
− −
2 2
2 2
y y
N x
x N
y x
xy N
